JP2012531553A - Method for switching liquid ring pump with liquid discharge port - Google Patents

Abstract

A liquid ring pump that discharges sealing liquid (compressed fluid) from a pump operating chamber to a liquid ring pump having a gas discharge system by reassigning the function of a selected path of the liquid ring pump. Switch.
The route is selected from a group of routes consisting only of (1) a sealing liquid introduction path and (2) a sealing liquid discharge path.
[Selection] Figure 4

Description

  The present invention generally relates to a liquid ring pump ("pump") that discharges a liquid seal (compressed fluid) from a working chamber of the pump. More specifically, the present invention relates to a method for switching from a liquid ring pump using a sealed liquid discharge system to a liquid ring pump using a gas discharge system in order to cope with a changing compression ratio.

  Liquid ring pumps are well known. Bissell U.S. Pat. No. 4,498,844 discloses a liquid ring pump having a conical port member. This conical port member has a recirculation discharge port in addition to the conventional intake and discharge ports. U.S. Pat. No. 4,498,844 is incorporated herein in its entirety.

  The pump shown in FIG. 1 is a known configuration of a conical liquid ring pump. FIG. 1 is a vertical cross-sectional view along a plane parallel to the axis of the pump. FIG. 1A shows that the cross section is a cross section along line 100. Accordingly, the section line 100 provides the perspective of FIG.

  The pump has a first head 20 and a second head 22. Each head has gas inlets 20a and 22a. Each head has gas discharge ports 20b and 22b. The heads 20 and 22 are located at the shaft end of the liquid ring pump. Located between the axial directions of the pump heads 20, 22 is a body or housing 23. Located in the housing is a rotor 25. The rotor 25 has a rotary blade 25a. The rotor blade 25a extends from the hub 25b.

  The main body or housing 23 provides a chamber (working chamber), the rotor 25 rotates, and air or gas 26 is drawn into the working chamber through the gas inlets 20a, 22a. The gas 26 is exhausted from the working chamber through the gas discharge ports 20b and 22b.

  As can be seen from the above, the gas 26 is drawn into the working chamber through the conical port members 27, 28. Further, the gas is exhausted from the working chamber through the conical port members 27 and 28. The chamber is divided into a first working chamber 23a and a second working chamber 23b by a rotor shroud 25c and a lobe shroud 23c.

  Referring to FIG. 2, the sealing liquid 29 is in the working chamber. As the rotor 25 rotates, the sealing liquid 29 is sealed in the working chamber. The liquid seal has an eccentric shape that is dispersed and converges in the radial direction with respect to the shaft 30 of the liquid ring pump. In the portion where the sealing liquid 29 is dispersed from the shaft 30, the reduced pressure generated in the space (bucket) between adjacent rotor blades of the rotor assembly constitutes a gas suction section. In the portion where the sealing liquid 29 converges on the shaft 30, the rising pressure generated in the space (bucket) between adjacent rotor blades constitutes a gas compression section. Schultz US Pat. No. 4,850,808 provides an example of a conical liquid ring pump. U.S. Pat. No. 4,850,808 is incorporated herein in its entirety.

  The liquid ring pump shown in FIG. 1 has a seal liquid inlet or introduction path 31 so that the seal liquid 29 can enter the working chamber. Seal liquid 29 passes through the head and the conical port member. Although the sealing liquid 29 is shown as entering only through the head 20 and the conical member 27, it can also enter through the head 22 and the conical member 28.

  In addition to having the sealing liquid introduction path 31, the pump of FIG. 1 also has a liquid discharge passage so that liquid can be discharged from the working chamber when the pump is operated. FIG. 2, which is the prior art, shows a schematic view of the sealing liquid 29 exiting the working chamber through the sealing liquid discharge passage 33. The existing heads 20, 22 are symmetrical with respect to the vertical axis, allowing a design where one head can be used at either axial end of the pump. Depending on the direction of rotation, the path in the head is generally used for either introduction or discharge of the sealing liquid 29.

  The design compression ratio is the ratio of the design discharge pressure to the design suction pressure. The compression ratio during operation is the ratio of the discharge pressure during operation to the suction pressure during operation. In practice, the pressure at the discharge port remains constant and is usually atmospheric pressure. The suction pressure varies depending on the application.

  In a pump having a fixed discharge port, it is known that the pressure in the working chamber increases when the compression ratio during operation is smaller than the designed compression ratio. As pressure increases, additional pump power must be used. In order to minimize the need for extra pump power, the prior art shown in FIGS. 1 and 2 has a compressed fluid (sealing) discharge passage or a built-in leakage path to remove the sealing liquid from the working chamber. The pressure in the working chamber and bucket can be reduced. In this way, by discharging the sealing liquid, a change in the compression ratio that occurs in the pump during operation is dealt with.

  The use of a compressed fluid or seal discharge passage (leakage path) has several drawbacks. In order to obtain an appropriate pressure in the working chamber, an equilibrium operation for continuously opening and refilling the sealing liquid is required for discharging. When the flow rate of the sealing liquid exceeds the normal flow rate, the output control function of the liquid discharge means exceeds the limit, and the pump power increases at a low compression ratio that overloads the drive system. Further, when the vacuum pressure rapidly decreases from the designed compression ratio to the low compression ratio, the liquid in the pump enters a period that is greater than the steady state low compression ratio state. Excess liquid overloads the drive equipment. Also, when the liquid seal to the pump is reduced, the outflow through the liquid discharge passage loses the seal in the pump and reduces the amount of gas delivered.

  The present disclosure provides a switch from a liquid ring pump using sealed liquid discharge to a pump using gas discharge. Gas discharge eliminates the need for continuous introduction and opening of the sealing liquid to some extent, thus preventing problems associated with sealing liquid discharge. On the other hand, when the pump operates at a compression ratio smaller than the designed compression ratio, the gas can be discharged from the working chamber of the pump to reduce overcompression. As a result, shaft power requirements are also reduced. Switching to an existing liquid ring pump can only be done with minimal changes to the pump components.

  The seal path of the liquid ring pump used for either seal liquid discharge or seal liquid introduction is reassigned to function and forms part of the gas discharge. In the present disclosure, it is shown that the function of the sealing liquid introduction path in the pump head is reassigned to be a part of the gas discharge path. The present disclosure also provides switching from the sealing liquid discharge passage of the existing liquid sealing pump to the sealing liquid introduction path.

  In order to switch from the sealing liquid discharge passage to the sealing liquid introduction passage, it is necessary to provide a new cone that seals a part of the discharge passage extending through the pump head. This new cone provides a new flow path and allows the seal to enter the working chamber from the path in the pump head that was used to form part of the seal drain passage. Of course, the passage reassigned the function to the sealing liquid introduction passage is re-piped to receive the sealant.

  To provide gas discharge, the path of the pump head that was used to introduce the seal is reassigned to form part of the appropriately sized path for discharging gas to the pump outlet. . In addition, the new cone has an opening for introducing the sealing liquid, but now has a discharge path aligned with the opening in the pump head whose function is reassigned as an opening for discharging gas in the pump head. The new cone gas path has a gas outlet through the cone cone face.

  Pumps that have been reallocated and switched can operate even when the seal flow to the pump is low, because the pump no longer relies on seal discharge to cope with variations in compression ratio. Also, by reassigning the function, the pump can be operated at a sealing liquid flow rate of 200% or more of the pump before reassignment, exceeding the vacuum range of the entire operation of the pump, without increasing the power requirement over the pump of the prior art. can do. As a result, the pump after reassignment is less likely to react to the doubling of the sealing rate and less likely to react to a sudden vacuum drop.

FIG. 1 is a longitudinal sectional view of a prior art liquid ring pump along a plane parallel to the pump shaft. FIG. 1A is an end view of a pump head of the type shown in FIG. FIG. 2 is an enlarged schematic view of a part of the pump shown in FIG. 1 and shows a sealing liquid discharge passage through which sealing liquid around the rotor can be discharged. FIG. 3 is a horizontal cross-sectional view of a pump of the type shown in FIG. 1 taken along a plane parallel to the pump shaft, which includes a pump head coupled to a conical member. FIG. 4 is a horizontal sectional view seen through the liquid-sealed pump taken in the same manner as the cross-section of FIG. 3 so that the pump head and the cone can discharge gas to the flow path used for introducing the liquid-sealed liquid. Reconfigured according to the present invention. FIG. 5 is an isometric view of the conical member shown in FIG. FIG. 6 is an end view of the conical member shown in FIG. 5, and is a view of the inside of the tip or the small end of the cone. FIG. 7 is an isometric view of the cone shown in FIG. FIG. 8 is an end view of the cone shown in FIG. 7, and is a view of the inside of the tip or the small end of the cone. FIG. 9 is an end view of a pump head of the type shown in FIG. FIG. 10 is an end view of the pump head after reconfiguration of the type shown in FIG.

  The present invention switches from a pump that relies on a sealed liquid discharge passage, also known as a leakage path, to a pump that uses a gas discharge path. Here, the gas discharge path is used to cope with a changing compression ratio instead of the sealing liquid discharge path. Prior to pump switching, the pump has all the features shown in FIGS. FIG. 3 shows a pump head 40 having a sealing liquid (compressed fluid) discharge passage before switching. The discharge path or path is formed by a flow path 41 a extending through the pump head 40 and an opening 41 b extending through the flange 44 of the conical member 46. The unnecessary sealing liquid 29 can be discharged from the working chamber through the discharge path.

  Before switching, the pump head 40 also has a sealing liquid introduction path. The sealing liquid introduction path is formed by a flow path 48 a extending through the pump head 40 and a flow path 48 b extending through the conical member 46.

  In order to switch from the pump shown in FIGS. 1 and 3 to the gas discharge type liquid ring pump, a new conical member 50 as shown in FIGS. 4, 7 and 8 is provided. Further, the pump head 40 is reconfigured by possible machining or the like so that the function of the sealing liquid introduction channel 48a is reassigned to form a part 448a of the gas discharge path. The new cone 50 forms another part 448b of the gas discharge path. The cone path 448b has a port 448b 'through which exhausted gas enters the cone path 448b. As shown in FIG. 10, the gas discharge path may include a conduit 55, and the gas exiting the reassigned pump head 440 through path 448 a may terminate at the pump outlet 56 or the exhaust piping system 58. it can. As shown, the pump of FIG. 10 has a main discharge port 73.

  Whether or not the provided passage has a sufficient area for discharging gas from the working chamber in providing a gas discharge passage that passes through a part of the pump head 40 used as a part of the sealing liquid introduction passage. It is important to confirm. The smaller the path, the greater the pressure required at the gas port 448b 'and the greater the power required for the vacuum pump to obtain that pressure at the port 448b'. High power means increased work costs for end consumers. Experiments show that when the ratio of pump capacity to passage area is between 490 and 1,160 CMF per square inch, there is an appropriate cross-sectional path. Preferably, no part of the path has a restricted area outside the desired ratio range.

  As best seen in FIG. 8, in a cone 50 that includes a single discharge opening 448b ′ and is designed to operate in a 20 inch mercury vacuum, the forward end 448b ″ of the opening in the cone, The angle must be between 130 and 140 degrees before the closest point between the rotor blade 25a and the rotor body 23. The closest point of the rotor body is approximated by line 60. The direction of rotation is indicated by arrow 61. The angle of the closed end 448 b ″ ″ of the discharge opening (port) 448 b ′ is preferably 110 to 115 degrees before the closest approach between the rotor and the main body. The angle included from the closing part of the discharge opening to the opening part of the last outlet 70 of the cone is around the angular distance between two consecutive rotor blades with a tolerance of 7 degrees. The inlet is shown at 71.

  The new cone 50 is provided with a sealing fluid channel 441b, and the sealing fluid 29 can enter the working chamber through what has been used as the compressed fluid discharge channel 41a. In this way, a part of the compressed fluid discharge channel 41a is reallocated to the sealing liquid introduction channel 441a. The pump 40 is reconfigured so that the compressed fluid discharge channel 41a is partially sealed with 41a '. The cone 50 seals a portion 41a 'of the discharge path 41a by providing a cone flange 444 in which the discharge port 41b is omitted. Thus, the flange 444 seals the discharge part 41a with 41a '. Currently, the passage reassigned as the sealing liquid introduction passage 441a is re-pipe as shown in FIGS.

  As used herein, the term gas is broad enough to include air.

  While embodiments of the invention have been disclosed, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

  All features disclosed herein (including the appended claims, abstracts and drawings), and / or every step of the disclosed method or process, wherein at least some features and / or It can be used in all combinations except combinations where the steps are mutually exclusive.

  Each feature disclosed in this specification (including the appended claims, abstract and drawings) may be replaced with an alternative feature serving the same, equivalent or similar purpose unless otherwise indicated. . That is, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

  The present invention is not limited to the details of the foregoing embodiments. The present invention is directed to all novel or all novel combinations of features disclosed herein (including the appended claims, abstract and drawings), or to all disclosed methods or processes. Expand to all new or all new combinations of all processes.

Claims (14)

A method for switching from a liquid ring pump using a liquid discharge to a liquid ring pump using a gas discharge,
Removing the conical port member from the pump head of the liquid ring pump;
A method comprising the steps of: (1) selecting a path in the pump from a group of paths including only a sealing liquid introduction path and (2) a sealing liquid discharge path, and reassigning the function of the gas discharge path to the selected path.   The method of claim 1, wherein the function reassignment step includes mounting a conical member on the pump head, wherein a port of the conical member forms part of the gas discharge path.   The method according to claim 2, wherein the route selected for the reallocation of the function is the route that forms the sealing liquid introduction route.   The method of claim 1, wherein the function reassignment step includes machining a flow path in the pump head, the flow path forming part of the selected path.   The method according to claim 1, wherein the function reassignment step includes a piping step of the gas discharge path.   4. The method according to claim 3, further comprising the step of reassigning the function of a flow path forming a part of a new sealing liquid introduction flow path to the flow path forming a part of the sealing liquid discharge path.   The step of reassigning the function to the flow path forming a part of the liquid discharge path includes sealing a part of the flow path forming the discharge path having a flange of the conical member. The method of claim 6 characterized in that:   The method according to claim 6, wherein the function reassignment step includes machining of the flow path forming a part of the sealing liquid discharge path.   The step of reassigning the function to the flow path forming a part of the sealing liquid discharge path includes aligning the sealing liquid flow path in the conical member to form a part of the sealing liquid introduction path. 8. The method of claim 7, comprising: (1) A path in the pump head serving as a gas discharge path of a part of a pump to which a function is reassigned from a path selected from a group of paths including only a seal liquid discharge path and (2) a path including a seal liquid discharge path When,
A pump head of a liquid ring pump in combination with a conical port member provided with a port in the conical member that becomes a part of the gas discharge path.   A flange of the conical member that seals a flow path adjacent to a sealing liquid introduction flow path in the pump head; and the sealing liquid introduction flow path in the pump head is a sealing liquid flow in the conical port member. The combination of claim 10, wherein the combination is fluidly connected to the channel. A rotor having two successive rotor blades;
The port of the conical member has a closed end, and the angular distance from the closed end to the opening of the last outlet in the conical member is the two consecutive rotor blades of the pump with a tolerance of 7 degrees The combination of claim 10, wherein the combination is an angular distance between.   A rotor and a housing body are further provided, and the conical member has a closed end of preferably 110 to 115 degrees before the closest approach between the rotor blades of the rotor and the housing body of the pump. 10. A combination according to 10.   A rotor and a housing body are further provided, and the port of the conical member has a front end, preferably 130 to 146 degrees, before the closest point of the rotor blades of the rotor and the housing body of the pump. The combination according to claim 10.

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